1. Field of the Invention
The present invention relates to a discharge unit for sequentially discharging a lowermost piece of a stack of these pieces superposed in a shaft, the pieces in the stack having a predetermined dimension and the shaft having an inner cross section corresponding to this dimension and a lower end wherefrom the lowermost pices are sequentially discharged, the lower shaft and defining a plane. The discharge unit comprises an axle extending in this plane, a bell crank lever having a first arm and a second arm, the bell crank lever being supported on the axle for pivoting between a first position wherein the first arm projects into the inner cross section of the shaft to hold the lowermost piece in the shaft and a second position wherein the first arm is retracted out of the inner shaft cross section to release the lowermost piece for discharge therefrom from the shaft, and a clamping device arranged to be movable relative to the shaft to clamp the piece superposed over the lowermost piece in position to hold the stack in the shaft.
2. Description of the Prior Art
Such a discharge unit has been disclosed, for example in Swiss patent No. 654,274. According to this patent, the clamping device is constituted by a pair of clamping bell crank levers, a side of one of whose arms facing the piece superposed over the lowermost piece of the stack to be discharged is engageable therewith. This pair of clamping bell crank levers is controlled in unison with a pair of bell crank levers having an arm projecting into the inner cross section of the shaft in a locking position wherein these arms support the stack of pieces in the shaft. One of the bell crank levers of each pair are pivotally arranged on a common axle, all the levers are biased against assuming their respective clamping and locking positions and rotating cams control their pivoting movements.
This structure has the disadvantage of considerable structural complexity. Furthermore, the control cams require relatively much space adjacent the shaft holding the stack, which imparts considerable width to the unit.
German Democratic Republic patent No. 260,267 discloses a discharge unit for sequentially discharging a lowermost piece of a stack of these pieces superposed in a shaft from a lower shaft end, which comprises two plates movable perpendicularly to the shaft at the shaft end. A lower one of the plates projects into the inner cross section of the shaft in a locking position and an upper one of the plates has a side engageable with the stack to clamp it in position. The two plates are coupled together by two bell crank levers and are alternately movable in opposite directions perpendicularly to the longitudinal axis of the shaft. This structure too, requires considerable space adjacent the shaft.